The present application relates to a rechargeable battery. More particularly, the present application relates to a high-capacity rechargeable lithium-ion battery including an anode structure composed of a substrate that includes a porous semiconductor region with two different porosities and a non-porous semiconductor region located beneath the porous semiconductor region.
In recent years, there has been an increased demand for electronic devices such as, for example, computers, mobile phones, tracking systems, scanners, medical devices, smart watches, power tools, remote systems and sensors, electric vehicles, internet of things (IOT) and fitness devices. One drawback with such electronic devices is the need to include a power supply within the device itself. Typically, a battery is used as the power supply of such electronic devices. Batteries must have sufficient capacity to power the electronic device for at least the length that the device is being used. Sufficient battery capacity can result in a power supply that is quite heavy and/or large compared to the rest of the electronic device. As such, smaller sized and lighter weight power supplies with sufficient energy storage are desired. Such power supplies can be implemented in smaller and lighter weight electronic devices in combination with lithium ion materials acting as the charge carrier; as lithium is the lightest and most electropositive charge carrier ion in the Periodic Table of Elements, lithium ion batteries and capacitors are considered the best fit for smaller, more energy dense energy storage devices.
Aside from the demand for lightweight energy storage devices that yield high energy density (high capacity), the need for faster charge rates (i.e., high speed charging kinetics) is also a current demand in the consumer market. For the next generation of batteries, it would be desirable if the battery was able to be fully charged in ten minutes or less in order to meet the needs of consumers in markets such as electric vehicles, portable telecommunications, IOT, and sensors. In the case of electric vehicles, if a consumer must wait longer than ten minutes to charge his/her vehicle, the battery powered electric vehicle may impose a limitation on the user's timeline and consequently, their travel range. Hence, fast charge rates of batteries used in the electric vehicles market would help create a viable electric vehicle market that would compete with and perhaps substitute for gas-powered automobiles.
Another drawback of conventional batteries is that some of the batteries contain potentially flammable and toxic materials that may leak causing safety hazards and expensive product recalls. As a result, these batteries may be subject to governmental regulations and cause damage to product reputation. The battery leakage risks can increase due to cracks forming within these batteries. These cracks are most likely caused by internal stress due to the battery charge/discharge cycles.
In addition and in the case of batteries containing a solid-state electrolyte, there is evidence that battery lifetime performance is decreased due to dendrite formation within these batteries. Dendrite size increases over the lifetime of the battery and most likely relates to the number of charge/discharge cycles of the battery as well. As dendrites form within the battery and grow larger over time, the dendrites tend to electrically short the internal components of the battery, causing battery failure.
With the advent of lithium metal charge hosting electrodes, which provide stable, charge hosting of lithium metal and facilitate the reversible ionization mechanism of lithium ions into lithium metal, and vice versa, sustainable all-solid state or semi-solid state lithium ion batteries are attainable for mass production in consumer markets. Lithium metal maintains a theoretical energy capacity of 3850 mAh/g, whereas silicon-based lithium-hosting electrode materials maintain a theoretical capacity of 4200 mA/g. Both of these materials acting as an anode, for example, are greater than ten times the theoretical capacity of conventional graphitic anode materials (372 mAh/g). However, these batteries still have the risk of cracking, leakage, and internal dendrite failure.
Hence there is a need for an improved lithium-ion battery to provide an electrical power supply that has reduced charge times, has higher storage capacities, and is safe and rechargeable over many charge/discharge life cycles with reduced risk of cracking, leakage, and failure due to dendrite growth within the battery.